Although flattened by a left hook in the fourth and staggered by the same punch in the eighth, 10th and 11th rounds, the 26-year-old Khan (28-3, 19 KOs) outscored the 33-year-old Diaz (40-8-1, 29 KOs) by counts of 115-113, 115-112 and 114-113.

Khan, who last fought in Britain two years ago in a winning effort against Irishman Paul McCloskey, is a human chandelier capable of getting floored at any moment with one decisive shot to the kisser.